Gas and air mixing apparatus.



No. 770,740. I PATENTED SEPT. 27, 1904.

. C. G. DODGE. GAS AND AIR MIXING APPARATUS.

APLIOATION FILED JUNE 26, 1903.

N0 MODEL.

I zo O/f X 15 ,0' f e Patented September 27, 1904.

PATENT OEEICE.

CHARLES O. DODGE, OF NEW YORK, N. Y.

GAS` AND AIR MIXING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 770,740, dated September 27, 1904.

Application filed June'ZG, 1903. Serial No. 163,233. (No model.)

To (o7/Z whom, it may concern:

Be it known that I,CHARLES O. DoDGE,a citi.- zen of the United States, residing at New York city, in the county and State of New York, have invented certain new and useful Improvements in Gas and Air Mixing Apparatus, of which the following is a specification.

This invention relates to gas and air mixing apparatus'of that kind in which a gasmeter drum and an air-meter drum are mounted on the same shaft in acasing and in which pressure of gas is utilized directly for revolving the gas-drum, and thereby revolving the air-drum, for mixing gas and air or gaseous iiuids of different gravities in the desiredv proportions to obtain a .perfectly homogeneous mixture of gas and air for heating and illuminating purposes.

I am familiar with Patents No. 556,490, March 17, 1896, and No. 651,779, June 12, 1900, for Apparatus for mixing gas and air and fully recognize their importance so far as they reach in covering apparatus for accomplishing the objects described by using the gas-pressure as a motive power for revolving an air-drum. I will now describe the operation of the apparatus covered by the above patents, so that any one familiar with the art can appreciate the importance of my present improvements. In these two patents the gas and air meter drums are both arranged for simultaneous sealing at both ends the screw measuring-compartments in the sealing liquid when in full action and would work well except for the differential pressures in the gasdrum and the surrounding casing. The gas entering the gas-measuring compartment is always under the full pressure from the city mains. The airis drawn into the air-measuring compartment under no pressure, the airdrum being operated by the gas-pressure only in the gas-drum,'the two proportioning drums being connected and operated upon one shaft, so that the gas-pressure performs all the work. As 4soon as the air-measuring compartments commence to displace the air by the resistance of the sealing-water or other liquid in the containing-cylinder the air is placed under pressure and is so discharged under the same pressure as the gas from the corresponding gascompartments, because by the simultaneous sealing and discharging in the compartments of the gas-drum the pressure is cut off from the inlets of the measuring-compartments andv only delivers the gas by resistance against the sealing liquid at the same pressure as that in the air chamber or drum. The pressure is maintained in the two following compartments of the gas-drum, filling up with gas as they ascend out of the water, the inflowing gas acting as the motive power. It will be readily seen that the gas-pressure not only operates the gas-drum, but has to operate the air-drum, which has from three to five times the capacity of the gas-drum, and the pressure is absorbed in the same ratio, producing little pressure at the burner. The gas enters the gas-measuring compartments at full force or pressure and is discharged under a low pressure into the mixing-chamber. This gives two pressures of gas to contend with, and as soon as the gas is turned olf at the burner the pressure increases in the gas-chamber and under the construction set forth in the two patents breaks through the liquid seal near the center of the head around the gas-inlet pipe and fills the mixing-chamber and pipes with an increased proportion of illuminating-gas. This defective operation seriously interferes with the proper proportioning and mixing of the gas and air and would make it necessary to turn off the gas by a stop-cock in the supply-pipe behind the meter every time the gas was turned off at the burners.

The object of my improvements is to hold the gas in full abeyance in the gas-chamber of the gas-drum at all times and under any pressure, so that the measuring-compartments can pass gas only when the mixture is being used at the burners. By completely controlling the gas-pressure I increase the pressure of the gas and air mixture and hold it under pressure at all times substantially the same as the illuminating-gas, producing a gas and air mixer that would at all times be operative and fully automatic. In order to accomplish this, I arrange two or more liquid seals at the central opening in the head of the gas-drum to fully obstruct any desired gas-pressure without friction in the revolution of the gas IOO and air mixing drums. I also provide for giving to the gas and air drums the required buoyancy to float them, so that a low pressure of gas will readily revolve either small or large mixing-drums.

The particular devices and combinations thereof constituting my invention herein will be defined in the claims.

My improved apparatus will now be described by reference to the accompanying drawings, in whichM Figure l represents a vertical longitudinal section of the casing' and meter-drums with the gas and air inlet pipes in elevation. Fig. 2 represents a transverse section through the casing and one end of the gas-meter drum on line m .ft/, Fig. l. Fig. 3 represents an end elevation at the inlet end of the gas-meter drum with parts broken away. Fig. 4 represents a partial end elevation at the discharge end of the gas-meter drum. Fig. 5 represents a sectional detail view, on enlarged scale, of the seal devices. Figs. 2, 8, and 4 are on a reduced scaley as compared with Fig. l.

The outer cylinder or casing A, which contains the gas and air drums, is preferably constructed of two half-cylinder sections provided with longitudinal flanges a, which are held together by a rivet or bolt, as indicated in Fig. 2. The casing A is preferably supported on short legs a. The two halves of the casing A are provided centrally at their ends with openings or notches and outwardly-turned flanges, into which notches are set the angular central hubs @"f provided with inner and outer fianges d", for making tight joints with the flanges a4, projecting from the heads of the casing, as shown in Fig. 1. With these angular hubs a connect the inlet gas-pipe E and the inlet air-pipe F, also interior elbow-pipes e and f for admitting gas and air to the interior of the drums B and C. Within the casing A I mount the gas-meter drum B and the airmeter drum C on the same horizontal shaft D. The shaft D is pivotally mounted at its ends in thebearings d and CZ', projecting inward from the horizontal portion e and f of the elbowpipes. The pivotal bearings are such as to permit the shaft and drums to turn with the least possible amount of friction.

The gas-drum B may be styled the drivingdrum and serves the purpose of measuring gas and driving or revolving the air-drum, and the drum C may be styled the inductiondrum and is for measuring and delivering air to be mixed with gas in the space X between the two drums.

of which they may be slipped upon and suitably secured to the shaft D. Both of the cylinders or chambers H and K are air-tight and serve as floats or buoys for sustaining or floating the gas and air drums in the sealing Water or other liquid which is placed in the casing A. The object of thus fioating or buoying up the gas and air drums is to remove the weight and pressure from the shaft D and its bearings, and thus overcome resistance to the free revolution of the drums in the casing A.

The g'as-drum is constructed with a head B', which is tightly closed except at the -center, where it is provided with an opening' 6 of greater diameter than the horizontal portion e of the elbow-pipe c, as shown in Figs. l and 5. This opening 5 is required for permitting' the head B' to freely turn around the part e'. The ordinary stufling-box provided with packing cannot be applied to the head of the drum at this point, for the reason that it would produce too much friction and retard the free revolution of the drum. I therefore provide a liquid seal or packing at this point for preventing high-pressure gas from passing backward from the gas-chamber?) through the opening 5 into the outer casing. To overcome this diicultyl provide a liquid seal by fitting tightly upon the hub e of the elbowpipe a circular plate or disk Z, as shown in Figs. l and 3. This plate may be made of metal and strengthened by central rings or a thickened portion, as indicated in the drawings. This disk Z is inclosed within a liquid seal-chamber G, which is made by securing to the head B a circular disk head b, having inwardly-turned flanges n, as shown in Fig. l.

The flanges n of the head are tightly soldered or otherwise secured to the head B. The head is also provided with a central opening n of greater diameter than the hub e. By means of this construction I form two sealing-compartments g and g for containing water or other sealing liquid which may be placed in the casing A. A double seal is thus formed IIO around the hub e for the central opening in the head B. It 'will be understood that by means of this sealing device no friction is produced to retard the revolution ofthe gas and air drums. This seal also effectively prevents the escape of gas from the gas-chamber through the opening 6" into the casing A. By means of this sealing device also the water-line in the casingArnay be carried at a lower level, and therefore leave a larger space above the water-line for measuring and mixing gas and air. This is an important advantage in this kind of apparatus.

The screw-blades l, 2, 3, 4, and 5 of the gasdrum are tightly secured to the periphery of the central air-chamber H and at their outer edges to the interior of the drum B and form between them the screw measuring-compartments. Each screw-blade extends helically from the receiving or inlet end of the drum IZO ISO

' as indicated by the arrows in Fig. l.

a little more than one-half turn to the discharge end of the drum and are preferably so set as to make narrow inlets a at the receiving end and wide outlets w at the discharge end of the drum, as indicated in Fig. 1. Each of the screw-blades is preferably provided with a driving shoulder or offset L, as indicated in Fig. 2. The screw measuring-compartments are formed by the adjacent helical blades and extend from the narrow inlets u to the wide outlets w. At the outlet end of the drum B each of the blades is provided with a notch or opening m comparatively near the air-chamber H, as shown in Figs. 1 and 4, for causing the gas to escape from the measuringcompartments comparatively near the center of the drum, so as to better mix with the air which is being discharged from the drum C, It will be understood that the edges of the blades near the wall of the drum rise out of the wa-` ter a little later than the openings or notches m, so that the gas will be first discharged through said openings m.

The air inducing and measuring drum C is provided with a receiving-chamber 0 at the inlet end into which projects the inlet air-pipe f and with five helical screw-blades, forming between them screw measuring-compartments having narrow inlets .fr and wide outlets y. The blades of the air-drum extend helically a little more than one-half turn from the receiving end to the discharge end of the drum and are secured at their interior ed ges to the chamber K and at their outer edges to the wall of drum C.

The gas-meter drum and the air-meter drum being secured to the same shaft, the air-drum will be revolved by the pressure of gas on the blades of the gas-drum, which latter being revolved will drive or revolve the air-drum, thereby measuring and mixing positive and uniform proportions of gas and air for delivery through pipe L to the burners.

In the construction of the gas and air mixing' meters the gas-drum and the air-drum are so set on to shaft D that the outlets of the one drum are arranged to discharge midway between the outlets of the opposite drum. By this arrangement I obtain a positive sealing action in the compartments of both drums,

Y so that gas under pressure will never have a clear passage from the outlet of the gas-drum through any one of the measuring-compartments of the air-drum, for the reason that the measuring-compartments of the air-drum, which is discharging air, will be sealed at its inlet end and the measuring-compartment of the gas-drum, which is discharging gas, will at the same time be sealed at its inlet end.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a mixing-meter, one of the drums thereof having ahead provided with a liquid sealing device at its central opening, and a gas-inlet pipe passing through said opening, substantially as described.

2. rI he combination with a meter-drum, a casing and an inlet-pipe, of a liquid sealing device applied adjacent to the horizontal portion of said inlet-pipe, substantially as described.

3. The combination with the outer casing, the gas-inlet pipe and the gas-drum having an opening for said inlet-pipe, of a sealing-chamber on the head of the gas-drum and a plate or disk in said chamber, and secured to said inlet-pipe, substantially as described.

4. In amixing-meter, a drum constructed with a central closed chamber serving as a oat, and screw-blades between said chamber and the shell of the drum, substantially as described.

5. A mixing-meter drum provided with a closed air-chamber to serve as a float for buoying up the drum, substantially as described.

6. A mixing-meter drum constructed with a central closed air-chamber, having a longitudinal tube for mounting the drum on the supporting-shaft, substantially as described.

7. The combination with the outer casing and a suitably-supported shaft, of a meterdrum having a central closed chamber provided with a longitudinal tube for the shaft, said chamber serving as a buoy for the drum, substantially as described.

8. In a mixing-meter, the gas-drum constructed with screw-blades having notches or openings in their edges, toward the center, at the delivery end of the drum, substantially as described. A

9. In a mixing-meter, the combination with the casing and inlet-pipe, of the air-drum, and the gas-drum constructed with screw-blades having interior notches or opening's in their edges at the discharge end for causing escaping gas to be better mixed with air from the air-drum, substantially as described.

10. Agas and air mixing meter comprising a driving gas-drum and an induction air-drum, said drums, each having a closed air-chamber, mounted on the same shaft and serving as buoys for the drums. substantially as described.

In testimony whereof I have signed my name to this specification in presence of two witnesses.

` vCHARLES C. DODGE.

Witnesses:

WM. H. McDoNALD, Gmo. R. COTTRELL.

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